Is my caterpillar too small to form a chrysalis?
Sometimes an abnormally small caterpillar starts to form a chrysalis...will it be ok?
Best case scenario: As with people, some monarchs are just smaller than others and it will be fine
Worst case scenario: Your caterpillar might be compromised by a tachinid fly:
All you can do at this point is to wait to see what happens. good luck!